A. Field of the Invention
The invention herein disclosed and claimed relates to apparatus for inspecting the inner surface of tubular goods for possible defects. More particularly the invention herein relates to apparatus for generating, displaying and recording of video images of the inner surface of a tubular being inspected. With somewhat greater particularity the invention herein relates to apparatus having a dual field of view, whereby possible defects can be inspected both at acute and obtuse angles, under variable lighting conditions, and with increased magnification.
B. Description of Related Art
In the field of petroleum exploration, development and production literally miles of tubular goods are assembled, disassembled, reassembled, subjected to repeated handling and subjected to extreme downhole conditions. Suffice to say that the integrity of the tubular goods used in said processes is important, and the unexpected failure of a tubular is at best a nuisance, at worst can present life threatening risks.
As even small defects in a tubular can and often do worsen under the effect of corrosion, high pressure, tensile and compressive forces, erosion due to high velocity flows, etc., a need has arisen for careful inspection of tubulars to be used in such applications. Accordingly various techniques are employed in the inspection of tubular goods, including various electromagnetic techniques, techniques employing gamma rays, ultra-sound, etc. There has even been some attempt to visually inspect the interior of tubulars using manual borescopes and mirrors, but this has been generally found unsatisfactory due to the time and expense involved.
An object of the invention disclosed herein is to provide a video apparatus for, illuminating, displaying, inspecting and/or recording the interior surface of tubular goods. Another object of the invention disclosed herein is to provide an apparatus having a dual field of view, one field of which is comprised of a wide angle view of an axial section of nearly the entire circumference of the tubular for general viewing and the other field of view being a narrow angle view of a small section of the tubular, for enhanced inspection.